JPS59219778A - Electrochromic display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrochromic display device (hereinafter referred to as ECD).
). Among them, in particular, since multiple colors are displayed in one segment, kill variable colors EC, D
This is related to K.

The ECD according to the present invention is a dissolution-diffusion type 'ECD that applies the phenomenon in which an electrochromic material (EC material) contained in an electrolytic solution undergoes a redox reaction based on an electrode reaction and reversibly colors and discolors. . Recently, ECDs have been attracting attention because they can operate at low voltages and low power and provide bright and clear displays.

The structure of a typical conventional dissolving type ECD is shown in FIG. Generally, such an ECD includes a display substrate 1 and a counter substrate 202.
The two substrates are joined together via a spacer 7, and a sealing material 8
I was surprised to inject electrolyte 6 into the sealed cell. In such an ECD, in order to obtain a white background, a light reflecting plate is placed between the inner substrates, or an electrolytic solution is mixed with white powder and processed into a paste. The light reflecting plate is made of ceramic such as alumina or polymer, and the white powder is titanium oxide, alumina, etc. powder. These objects will be collectively referred to as light reflectors.

The display substrate 1 is generally a transparent substrate made of glass, plastic, or the like. A transparent electrode 3 is provided on this. This may be a tin oxide (SnO) film, an indium oxide-tin oxide (ITO) film, or the like, and is usually formed by vacuum deposition, but chemical methods such as spraying may also be used. Counter board 2
．． There are various structures for the counter electrode 4, but a typical example is a transparent chamber @! on a glass substrate. , a fully formed one, a metal film formed on a glass substrate, a pressed mixture of iron complex and carbon placed on a glass substrate, a metal plate 9, etc.

There are many possible methods for displaying a single numeric character, etc., but one method is to use a surface mask 5 such that only the portion of the patterned segment to be displayed is exposed to the transparent electrode 3 to the tPN liquid. There is a way to set it up. The surface mask material is mainly white ink made by dispersing white powder in resin, and is formed by screen printing. Furthermore, when displaying each segment separately, it is necessary to divide the display electrodes to which these segments are attached accordingly. Note that although a surface mask 5 is depicted in the figure, this is not essential.

As described in the paper, the electrolytic solution 4 contains a solvent, a support vehicle, and an E
It is composed of three components: C material. Any solvent can be used as long as it is highly polar and stable, and in addition to water, non-aqueous solvents such as propylene carbonate and dimethylformamide are used.

The case where a non-aqueous solvent is used will be mainly described below.

For support 1m, ordinary inorganic salts are used for water, but for non-aqueous solvents, alkali metals or tetraalkylammonium, perchloric acid CXO4, fluoroborate OF4. fluorophosphate PF,
Salt is used. EC materials include Na2WO4, Ca
Inorganic materials such as transition metal compound salts 9 such as WO4, BaWO, Na2MoO4, aromatic or heterocyclic compounds such as viologen, tetrathiafulvalene, pyrazoline, fluorene, anthraquinone, pyrylium, pyridium, methylene blue, and derivatives thereof, etc. There are organic materials and organometallic materials such as ferroinferrocene.

A conventional dissolving type ECD having such a structure displays only one color. For example, the initial state of an ECD using butyl anthraquinone in the ECU is white, and when a negative voltage is applied to the transparent electrode, the color develops into red, and when a reverse voltage is applied, the color disappears and returns to white. This white color is the color of the light scatterer.

ECDs that have been announced so far, not just dissolving type ECDs
Most display only one color.

As an ECD that produces multiple colors, one is known that has a structure in which a vaporized film of a complex of a lanthanoid metal and shiftalodianine is formed on a transparent upper layer. This type can display the three colors of red, #, and Tlf by changing the applied voltage, but there is no state where it becomes colorless and transparent or white, and the display colors are limited, making it difficult to diversify. There is little possibility of
It has the following disadvantages.

The purpose of the present invention is to provide an ECD capable of displaying a wide variety of colors.
t-To provide.

In the ECD of the present invention, three or more substrates or substrates each having a transparent electrode formed on at least one side are stacked so as to form two or more gaps, and an electrochromic material is applied to each gap formed between the substrates. and a supporting electrolyte dissolved therein, and a surface mask is provided in an area other than the pattern to be displayed on the display substrate, and on opposing surfaces of at least one pair of substrates forming a gap. A transparent electrode is formed on the substrate, and a counter electrode insulated from each of the electrodes is provided in a region between these substrates hidden behind the surface mask in the gap, and a counter electrode is provided in the gap. It has a structure in which an electrolytic solution in which an oxidative color-forming electrochromic material, a reductive color-forming electrochromic material, and a supporting electrolyte, which have mutually different coloring hues, are dissolved is injected and sealed.

Here, the display substrate is the substrate closest to the electrochromic display when viewing the electrochromic display according to the present invention. That is, it is one of the outermost substrates. In the case of an ECD viewed from both the front and back sides, the first substrate is the two outermost substrates.

A schematic cross-sectional view of an embodiment of the display device according to the present invention is shown in FIG.
As shown in the figure. A first counter electrode 12 made of a transparent electrode is formed on the display substrate 9. - A surface mask 11 made of a transparent or white insulating film is formed on the first display electrode 10 other than the pattern to be displayed. Alternatively, a white insulating film may be formed on the display substrate 9 in advance in an area other than the pattern to be displayed, and then the Vc81 display electrode 11 may be formed, but any structure may be used. on the other hand,
A fourth display electrode 19 is formed on the counter substrate 20 . An intermediate substrate 15 is inserted between the display substrate 9 and the counter substrate 2o, and a second display electrode 1 is provided on one side of the substrate.
4, a third display electrode 16 is formed on the other side.

In this example, the first counter electrode 12 was formed on the surface mask 11 on the first display electrode lo, and the second counter electrode 17 was formed on the insulating layer 21 on the third display electrode 16. This is not essential, and the same effect can be achieved by forming an insulating film on the second display electrode 14 and the fourth display electrode 19 in areas other than the pattern to be displayed, and forming the counter electrode thereon. One of the features of this embodiment is this structure in which a plurality of display electrodes are provided and a counter electrode is provided at a position hidden by the front mask.

This structure has the advantage that the electrodes can be made by vapor deposition, making it easy to manufacture and allowing the device to be made thinner. At least one is required for each, but depending on the display pattern,
An appropriate number is selected and the shape is determined as appropriate.

Between the two pairs of substrates are a first electrolytic solution 13 and a second electrolytic solution, which meet an oxidation coloring type (0 type) EC material and a reduction coloring type (R type) EC material, which have different color hues, and a supporting salt. 18 was inserted, which is another characteristic of this device.

Here, the type 0 Ec material is an EC material that is nearly colorless in a neutral state and develops color due to oxidation. The R-type EC material is an EC material that is nearly colorless in a neutral state and develops color by reduction. The display substrate, the display electrode of the counter substrate 1, the surface mask of the counter electrode 9, etc. used in this device can be formed using the same materials and manufacturing methods as those of the conventional device.

The operating principle of the first or second display electrode will be explained. The ECD according to the present invention has a fourth or second display electrode 10, 14
By applying an external voltage to the first counter electrode 12, the 0 type EC material develops color at the electrode to which a positive voltage is applied, and the R type EC material develops color at the electrode to which a negative voltage is applied. .

@1 Since the counter electrode 12 is not located under the surface mask 11, at least in the area corresponding to the pattern to be displayed, the color development on the counter electrode is not visible. Therefore, when a positive voltage is applied to the display electrode with respect to the counter electrode, the coloring hue of the θ-type EC material in the first liquid 13 becomes the displayed color, and when a negative voltage is applied, the R-type FJC The coloring hue of the material becomes the displayed color. When the applied voltage is set to Ov, the colored 0 type and R type EC materials react with each other, returning to a neutral colorless state and the display disappears.

The relationship between the voltage application to the third and fourth display electrodes 16 and 19 and the second counterelectrode 17 and the displayed color is that the first electrolyte 13 is
The only difference is that the electrolyte 14 is changed, and the rest is exactly the same as described regarding the first and second display electrodes 10.14.

In the ECD of this structure, independent voltages can be applied to the two display electrodes with the opposing electrode as a reference, so the color development can be controlled by the magnitude of the applied voltage, and the polarity of the applied voltage can control the R It becomes possible to obtain color development for type and θ type. From the above, by changing the polarity and magnitude of the voltage applied to the first and second display electrodes, the display color can be displayed by only the θ-type EC material in the first electrolyte, or the color can be displayed by only the R-type EC material. Colors and display colors can be obtained by varying the color development by the θ-type EC material and various mixing ratios by the R-type EC material. Similarly, by changing the polarity and magnitude of the voltage applied to the third and fourth display electrodes, it is possible to change the display color by only the 0-type EC material in the second electrolyte, or the display color by only the R-type EC material. Display color by color development,
It is also possible to obtain a display color by varying the mixing ratio of the color produced by the θ-type EC material and the color produced by the R-type EC material.

Therefore, the θ-type and R-type EC phases in the first electrolyte, the second i1E
If the coloring hues of the θ-type and R-type EC materials in solution are different from each other, the display color is based on the coloring of 44 groups and the mixing ratio of Yuzu between them. A wide variety of colors can be produced by voltage control.

In particular, EC uses 3m of these 4at coloring hues as the three primary colors of ink, yellow, red, and decolorization.
In D, these three colors can be displayed in various mixing ratios, so a full-color display can be obtained.

Further, as a special case, when the coloring hues of the EC materials of the first and second electrolytic liquids are the same, such a configuration 0ECD becomes an ECD that can obtain high contrast although the number of colors that can be displayed is small.

FIG. 3 is a schematic cross-sectional view of another embodiment of the ECDO according to the present invention, in which the counter electrode 14 is connected to the display substrate 9 and the counter substrate 1.
The only difference from FIG. 2 is the point provided between 0, and the rest are the same. In this way, the only requirement for the counter electrode is that it be insulated from other electrodes and provided in a position hidden behind the front mask, and is not limited to the configurations shown in FIGS. 2 and 3. . In such a structure 0ECD, the counter electrode 12.17 may be a counter electrode obtained by pressing a mixture of a transition metal complex such as an iron complex and carbon onto a metal plate such as platinum black or a titanium mesh wire. can. This structure allows the use of carbon-based electrodes with small potential fluctuations, so stable display can be achieved without display fluctuation.

Further, since it is only necessary to sandwich the electrodes, it has the advantage of being easy and inexpensive to manufacture.

In the above description, an example in which there are two gaps has been described, but there is also a structure in which the number of gaps is three or more by further increasing the number of substrates. When an electrolytic solution containing an R-type EC material and an O-type EC material with different color hues is injected into the gaps between the cells of this structure, in the case of an ECD with n gaps, the difference between them is based on the display color of 2nli. A wide variety of colors can be produced by voltage control, displaying colors with various mixing ratios. Also, EC material is R24
When only M or O type is used, the display color of an ECD with a similar number of gaps n is half of that when both R type and 0 type are used. In this way, by using both the R type and the 0 type, many display colors can be obtained with a small number of gaps.

In addition, in the ECD that displays the mixing ratio of three colors as described above, the four display electrodes 10, 14, 16, and 19 as shown in FIGS. 2 and 3 are not necessary; One electrode can be removed. A typical example of such a structure is shown in Section 4.
Shown in the figure. Furthermore, if chloronaphthoquinone is used as the E'C dye and tetrabutylammonium iodide is used as the electrolyte, the color of the iodine molecules produced by reduction will change, so there is no need to provide a counter electrode behind the surface mask. The color development of the R-type EC material is displayed with a structure in which the two are opposed to each other. A typical structure of such an ECD is shown in FIG.

The structure of the ECD according to the present invention is not limited to the structure described above, and various combinations are possible.

Here, the O-type EC material and R-type EC material used in the present invention are not limited to one type each, and multiple types of EC materials are used.
It can be used for both type or O type and R type. By such a mixture, a mixture of the color hues of each EC material alone can be used for display, and the variety of displays is significantly increased.

Hereinafter, the present invention will be explained based on examples.

Example 1 In FIG. 2, the display substrate 9. The intermediate substrate 15° and the counter substrate 20 are both glass plates. 2nd゜3rd. The fourth display electrodes 10, 14, 16, and 19 were all made of tin oxide/indium oxide (ITO), and were formed by vacuum deposition and processed into a desired pattern by chemical etching. Next, a white ink made of an epoxy resin containing titanium oxide was screen printed on areas other than the pattern to be displayed on the first and third display electrodes to form a surface mask 11 and an insulating layer 21. Further, as a counter electrode 14, a tin oxide/indium oxide (ITO) electrode was vacuum-deposited only on the surface mask 13.

The spacing between the three substrates 9, 15, and 20 was adjusted to about 30 to 100 μm, and they were sealed using epoxy adhesive.

The first electrolyte 13 contains 1-P-methoxyphenyl-3-p-diethylaminostyryl-5- as a zero plastic EC material.
Diethylaminophenyl-Δ2-pyrazoline (0,1~
0.3 mol/A), and 2-t-butylanthraquino 7 (0.1 to 0.3 mol/l) as the R-type EC material.

Tetrabutylammonium fluoroborate (0.05-0.2 mol/l) and tetrabutylammonium iodide (0.05-0.0,
2 mol/l), N-2-methyl-
Pyrrolidinone was used. The second electrolyte 18 includes type 0 EC
Tetrathiafulvalene (0.1 to 0.2 mol
/l), chloronaphthoquinone (0,
1 to 0.2 moL/L), supporting electrolyte and tetrabutylammonium fluoroboret) (0.05 to 0,
2 mol/z) and tetrabutylammonium iodide (0.05 to 0.2 mol/l), and N-2-methyl-pyrrolidinone was used as a solvent.

The initial state of this ECD is yellowish white or colorless. When applying a negative voltage of -2.OV to the first display electrode with respect to the first counter electrode and applying a voltage of -0.9V to 10.SV to the second display electrode, a red display was obtained. . A positive voltage of +2.0■ is applied to the first display electrode, and -0,
When a voltage of 9V to +〇, 8V was applied, a blue display was obtained. By applying a negative voltage of -1.0 to -2.5V to the first display electrode and a positive voltage of +1.0 to +2.5V to the second display electrode, it corresponds to the magnitude of the voltage of each polarity. Red, magenta, purple, 6 purple.

The evening display color was obtained. Next, for the second counter electrode,
When applying a negative voltage of -2.OV to the third display electrode and applying a voltage of -0.9v to +0.8v to the fourth display electrode,
A yellow color was obtained. +2 to the third display electrode. When a positive voltage of OV was applied and a voltage of 109 V to +0.8 cm was applied to the fourth display electrode, a brown display was obtained. By applying a negative voltage of -1.0 to -2.5V to the first display electrode and a positive voltage of +1.0 to +2.5V to the second display electrode, it corresponds to the magnitude of the voltage of each polarity. A mixed color of yellow and red was obtained. Also, from any display color state, the first. Second
The initial color was restored by applying OV to the display electrodes.

The contrast was approximately 2:1 for all displayed colors.

When all of the first to fourth display electrodes develop color, a mixed color of red, blue, yellow, and brown can be obtained depending on the amount of color development. The third display electrode is -1,0v~-2
, 5V negative voltage to the second display electrode from +1.0 to +2.5
Red by applying a positive voltage of v.

A mixed color of yellow and blue is obtained. Red, yellow, and blue are ink, etc.
Since they are primary colors, mixing these colors will give you a pure color.

Example 2 The structure shown in FIG. 3 was used instead of the structure shown in FIG. A prototype 0ECD with the same materials and structure as in Example 1 was manufactured, except that the substrate spacing was approximately 30 μ771 to INWA.

Display performance was the same as in Example 1.

Example 3 An ECD having the same materials and structure as in Example 1 was produced as a prototype, except that the composition of the 2' molten liquid was the same as that of the 1st molten liquid.

This ECD has the first and third display electrodes +2. When set to Ov,
The color develops in the evening, and when set to -2,OV, the color develops to red, and by applying a positive voltage to the first and third display electrodes and a negative voltage to the second and fourth display electrodes, it becomes blue. A mixed color of red is displayed. Although this ECD has fewer displayed colors,
A high contrast of 4:1 was obtained. Example 4 The same materials and structure as in Example 1 were used, except that benzo[α]anthracene-7112 dione was used as the R-type EC material of the second electrolyte. We made a prototype of ECD. The present EC and D were able to arbitrarily display each color of blue, red, brown, and green, as well as a mixture thereof.

Not limited to the EC materials listed in the above examples, various R-type and O-type EC materials could be used, and ECDs with various display colors were obtained. Also, one 1! Add one type of EC to either type 0 EC material or type R EC material, or both.
By using a plurality of EC materials instead of a single EC material, a mixed color of those EC materials can be used as the display color. Example 5 The structure shown in Fig. 4 was used instead of the structure shown in Fig. 2, and the 2nd turtle solution was used as an R-type EC material and chloronanobutquinone (0,
An ECD was prototyped using the same materials as in Example 1, except that propylene carbonate in which tetrabutylammonium iodide (0.1 to 0.2 mol/L) was dissolved was used. . and 0ECD is applied to the first display electrode with a positive voltage of +1.07 or more with respect to the first counter electrode. By applying a negative voltage of -1.0 V or less to the first counter electrode, the display becomes red, and by applying a positive voltage to the third display electrode with respect to the second counter' electrode, the display becomes yellow. will be displayed. As already mentioned, blue, yellow, and yellow are the three primary colors. Therefore, by adjusting the voltage applied to each electrode mentioned above, the coloring intensity of each color can be reduced to 0.
Any 67 of these colors can be AJI
, a gold-colored, full-color display was possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a conventional ECD. In FIG. 1, 1 display substrate 2 counter substrate 3 transparent electrode 4 counter electrode 5 surface mask 6 m'IN liquid 7 spacer
8 Sealing Material FIGS. 2, 3, and 4 are schematic cross-sectional views showing an example of the configuration of an embodiment of the present invention. In the figure, 9 display substrate, 10 first display electrode. 11 surface mask, 12 first counter electrode. 13 first turtle solution, 14 second display electrode. 15 intermediate substrate, 16 third display electrode. 17 second counter electrode, 18 second electric study liquid. 19 fourth display electrode, 20 counter substrate. 21 Insulating layer ゛・ , -・'

Claims (1)

[Claims] Three or more substrates or substrates each having a transparent electrode formed on at least one side are stacked so as to form two or more gaps, and an electrochromic material and a supporting electrolyte are dissolved in each gap formed between the substrates. The display substrate is filled with an electrolytic solution, a surface mask is provided in an area other than the pattern to be displayed on the display substrate, and transparent electrodes are formed on opposing surfaces of at least one pair of substrates forming a gap, and The structure includes a counter electrode insulated from each of the electrodes in a region hidden behind the surface mask in the gap, and
An electrochromic display device in which an electrolytic solution in which an oxidative color-forming electrochromic material, a reductive color-forming electrochromic material, and a supporting electrolyte, each having a different color hue, are dissolved is injected into the gap.